import pandas as pd
import numpy as np
import matplotlib.pyplot as plt

s = pd.Series(np.arange(1000) * -1)
print(np.abs(s))



df = pd.DataFrame( [
    [1, 2, 3, 4], 
    [5, 6, 7, 8],
    [9, 10, 11, 12]
],
index = ('first', 'two', 'three'),  
columns = list('ABCD'),
)

print(df)
print(df.head())


arr = np.arange(10)
np.save("arr", arr)
